On Nov 24, 1:04 pm, "Yegor Bryukhov" <[EMAIL PROTECTED]> wrote:
Hi,
> > Great! Welcome! What sort of library are you thinking of?
>
> Magnus - a package for finitely presented groups, may be.
We have talked to Tim Daly about this and so far nothing has happened
in that directory. At least there are python bindings for Magnus, so
that should make things easy.
> > It's a possibility. If there was a library that only worked for sparse
> > matrices, but the user wanted to use a function on a dense matrix, I
> > don't see any way around converting the matrix.
>
> > Of course, the user could ask for a sparse version of their matrix, then
> > call the library routine a thousand times, then convert back to dense,
> > if they wanted.
>
> There obviously, will be some common ground between Magnus and GAP, so
> the same group can be represented as a GAP object and as a Magnus
> object.
> I guess, I don't really understand who will be responsible for the conversion.
> ...
> Ahm, I've just looked at Sage's reference manual section on
> GAP-Singular connection (http://www.sagemath.org/doc/ref/node100.html)
> and I'm kind of unimpressed. It's ugly.
> It looks like the only benefit of using Sage is a common runtime
> environment across its libraries. Libraries' types are kept completely
> disjoint.
There is a lot of code in the Sage library that implements a lot of
mathematical algorithms, i.e. looks at modular forms for example. Some
people do believe that Sage is pretty much a way to do computations
with the included systems like GAP or Maxima, but that is only a small
part of the code base.
> Why not to do such translations (from a polynomial to a polynomial)
> transparently to the user?
The section you looked at is actually a pretty ugly example indeed and
with the current Sage getting objects from one system to another is
much more elegant. But in case of GAP there will likely not he a fast
way to convert objects as long as GAP cannot be used as a shared
library and since their interpreter and memory model is not designed
to do that it will not likely happen anytime soon. Note that a lot of
functionality in Singular is used in Sage via libSingular.
> --
> Best regards,
> Yegor
Cheers,
Michael
> __________________________________________________________
> Yegor Bryukhov,
> Research Associate
> Center for Algorithms and Interactive Scientific Software
> City College of New York
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